Wound healing has been the subject of extensive investigations since the beginnings of surgery. There are no simple models, however, that can be used to study this complex process. The goal of the research described in this proposal is to develop an in vitro model of wound healing in ski that can be used to study granulation tissue formation and re-epithelialization. The availability of such a model would facilitate testing of various treatments that might modulate the wound healing response. In addition, it would provide basic information on cell behavior during wound healing that might be useful in designing artificial skin. The proposed studies will require a combination of biochemical, immunological and light and electron microscopic analyses. During the project period, the questions listed below will be studied. (1) How are fibroblast morphology and migration into hydrated collagen gels affected by the incorporation of fibronectin and other extracellular martix components into the gels? (2) How are fibroblast morphology and migration into hydrated collagen gels influenced by the presence of whole blood clots or peripheral blood cells? (3) How are epidermal cell adhesion and migration on hydrated collagen gels affected by incorporation of fibronectin and other extracellular matrix components into the gels and/or the presence of other cell types in the gels? (4) What are the effects of cortisone acetate and some other reagents that modify cell function on granulation tissue formation and contraction?